1. Field of the Invention
The present invention generally relates to a prefilled, low particle, sterile, disposable syringe for injecting preparations with a fill volume of less than 5 ml. More particularly, the present invention relates to a syringe comprising a main body and a hypodermic needle, the body of the syringe being comprised of a grip, a nozzle, and a barrel equipped with an interior lubricating layer and an open end to accommodate a plunger that can be moved by means of a plunger rod within the barrel, and the hypodermic needle being mounted firmly within the nozzle, such that the needle penetrates the protective cap, forming a seal, while at the same time the interior of the cap sleeve fits tightly against the nozzle, also sealing the exterior surface of the needle. Furthermore, the invention concerns a procedure for the manufacture of such a syringe.
2. Description of the Prior Art
Prefilled, sterile, disposable syringes for medicinal purposes combine two different functions. On the one hand, they are suitable for storing highly effective preparations over a period of several years; on the other hand, they are also the instrument used to administer the preparations directly to the patient. Whereas in the case of vials and ampoules, preparations can only be administered after having first been drawn from the container by means of an empty syringe. The use of a prefilled, disposable syringe eliminates this filling process, i.e., pulling the plunger. In this way, the energy expended and the risks of confusing and of contaminating preparations are considerably reduced. In addition, when considering the "Total Cost of Drug Delivery," administering preparations directly from the container represents by far the most economical possibility.
Up to now only one example is known of a prefilled, disposable syringe of the type described in the introduction: the SCF (Sterile Clean Fill)--Staked Needle Injection by Becton Dickinson. The body of the syringe, i.e., the barrel, the grip, and the nozzle, consists of a single glass part, and for this reason the syringe is also called a prefilled, disposable glass syringe. Certainly in all known disposable syringes for injections of &lt;5 ml, the barrel at the very least is made of glass.
The needle of an SCF--Staked Needle Injection is glued into a corresponding recess in the nozzle. Disposable glass syringes are also known (e.g., German Patent Nos. DE 2,939,180 C2 and DE 3,916,101) in which the hypodermic needle is not directly integrated in the nozzle, but rather, is glued into an additional piece that can be mechanically connected to the nozzle. This increases the number of pieces and introduces an additional seam which must be sealed.
A major disadvantage of the disposable glass syringe is the risk of breakage and the related risks of injury and infection. Furthermore, many types of glass are not suitable for gamma ray sterilization, as the glass becomes permanently discolored. Gamma ray sterilization is, however, a very simple, economical and harmless sterilization procedure.
A further disadvantage of the disposable glass syringe is the costly procedure necessary to manufacture the glass components and to transfer them to a low particle, sterile environment. The manufacturing process for the glass components is slow and only allows for computer control and inspection in the beginning. The uncertainty of the process is equally as large. In addition to this, the glass components are continually in contact with equipment and lubricants, making a wash step absolutely necessary. The corresponding wash equipment requires a large capital investment and is expensive to operate.
Prefilled, disposable plastic syringes with total fill volumes of at least 50 ml are also known. Mallinckrodt's disposable hypodermic syringe, known under the brand name OPTIRAY, is not equipped with a hypodermic needle. Instead, infusion tubing is mechanically mounted on the nozzle. The plastic consists of (translucent) polypropylene.
The plastic barrel of the disposable syringe found in U.S. Pat. No. 4,861,335 is equipped with a plastic cap on the side of the barrel turned away from the plunger. The hypodermic needle is fastened to the cap by means of a mounting method known under the brand name LUER-LOCK. Therefore, the needle is not integrated with the nozzle.
For injections of considerably less than 50 ml, particularly for fill volumes smaller than 5 ml, the surface of the syringe is so large in comparison to the dispensed volume that the known prefilled plastic syringes could not be stored for long periods of time. The loss of preparation components from diffusion, particularly of water as a solvent, would be so great that the change in composition would be unacceptable. Furthermore, known plastic syringes are constructed from a translucent plastic, permitting only limited visual inspection of the syringe contents, which is an important step for low volume, prefilled disposable syringes. For this reason, only prefilled, disposable glass syringes are known for fill volumes under 5 ml.